The previous bolt in bar didn't make a lot of difference so simply moving it forward likely wouldn't make a lot of difference either. Thinking on the arrangement last night (over a dram of course to help the process) my feeling is that the rocking of the engine is moving the top tubes in the horizontal plane in synch with each other so the older style bolt in cross brace simply holds them in synch without really restricting the amplitude of the motion. The revised, welded in triangulated brace will stop that movement from the main cross brace forward to the pick up points on the main tubes. The new brace should do a similar job in that plane but the clamp on to the main cross brace will have to be good to do the job. It could be that the main cause of the fatigue problem is this constant rocking movement which is then exacerbated by suspension loadings. Just my thoughts...not the output from some fancy computer model.
